The Collaborative International Dictionary of English v.0.48:

Curling \Curl"ing\, n.
   1. The act or state of that which curls; as, the curling of
      smoke when it rises; the curling of a ringlet; also, the
      act or process of one who curls something, as hair, or the
      brim of hats.
      [1913 Webster]

   2. A scottish game in which heavy weights of stone or iron
      are propelled by hand over the ice towards a mark.
      [1913 Webster]

            Curling . . . is an amusement of the winter, and
            played on the ice, by sliding from one mark to
            another great stones of 40 to 70 pounds weight, of a
            hemispherical form, with an iron or wooden handle at
            top. The object of the player is to lay his stone as
            near to the mark as possible, to guard that of his
            partner, which has been well laid before, or to
            strike off that of his antagonist.    --Pennant
                                                  (Tour in
                                                  Scotland.
                                                  1772).
      [1913 Webster]

   Curling irons, Curling tong, an instrument for curling
      the hair; -- commonly heated when used. Called also
      curler[4].
      [1913 Webster]